The Philosophy Book

136 GOTTFRIED LEIBNIZ

Each singular substance

expresses the whole

universe in its own way.

Gottfried Wilhelm

Leibniz

faculties, human beings must
also rely on experience as a
means of acquiring knowledge.

A universe in our minds
To see how Leibniz arrives at this
conclusion, we need to understand
a little of his metaphysics—his
view of how the universe is
constructed. He holds that every
part of the world, every individual
thing, has a distinct concept or
“notion” associated with it, and that
every such notion contains within
it everything that is true about
itself, including its relations to other
things. Because everything in the
universe is connected, he argues,
it follows that every notion is
connected to every other notion,
and so it is possible—at least
in principle—to follow these
connections and to discover truths
about the entire universe through

rational reflection alone. Such

reflection leads to Leibniz’s “truths

of reasoning.” However, the human

mind can grasp only a small number

of such truths (such as those of

mathematics), and so it has to

rely on experience, which yields

“truths of fact.”

So how is it possible to progress

from knowing that it is snowing,

for example, to knowing what will

happen tomorrow somewhere on the

other side of the world? For Leibniz,

the answer lies in the fact that the

universe is composed of individual,

simple substances called “monads.”

Each monad is isolated from other

monads, and each contains a

complete representation of the

whole universe in its past,

present, and future states. This

representation is synchronized

between all the monads, so that

each one has the same content.

According to Leibniz, this is how

God created things—in a state of

“pre-established harmony.”

Leibniz claims that every

human mind is a monad, and so

contains a complete representation

of the universe. It is therefore

possible in principle for us to learn

everything that there is to know

about our world and beyond simply

by exploring our own minds.

Simply by analyzing my notion of

the star Betelgeuse, for example, I

will eventually be able to determine

the temperature on the surface

of the actual star Betelgeuse.

However, in practice, the analysis

that is required for me reach this

information is impossibly

complex—Leibniz calls it “infinite”

—and because I cannot complete

it, the only way that I can discover

the temperature of Betelgeuse is by

measuring it empirically using

astronomical equipment.

Is the temperature of the surface

of Betelgeuse a truth of reasoning

or a truth of fact? It may be true

that I had to resort to empirical

A map of the internet shows the

innumerable connections between

internet users. Leibniz’s theory of

monads suggests that all our minds

are similarly connected.